The Swedish indie-pop trio Peter BjŲrn and John write tales of sweetness and heartbreak on its breakthrough album.

Flip to the entry for Sweden in the encyclopedia and the description sounds almost utopian: phenomenal public schools, impossibly low crime rates and a universal healthcare system that could silence Michael Moore. At first listen, the music of Peter Björn and John, the country's freshly minted indie-rock poster boys, appears to reflect this idyllic existence. It's bubblegum pop that could pass as the latter-day Beach Boys: Foot-tapping percussion and jangly, hum-along guitar melodies are accented by maracas, bongos and whistling. But a closer listen reveals that these sugary-sweet arrangements coat mournful, introspective lyrics of regret  and loves lost and found.

Take "Young Folks," the single from the modestly named Scandinavians' latest release, Writer's Block. The song hints at skeletons in the closet: "If I told you things I did before/Told you how I used to be/ Would you go along with someone like me?"  a melancholic question that's starkly at odds with the song's blithe whistle and maraca-laden hook. The answer, sung as a duet with Victoria Bergsman, former frontwoman of fellow Swedish pop stars the Concretes, is an affirmation: "I would go along with someone like you/It doesn't matter what you did before." But for being a song about falling in love again, "Young Folks" remains haunted by self-doubt: Peter Morén, the group's primary singer and prodigious whistler, later sings, "Usually when things have gone this far, people tend to disappear." Of course, his reservations are juxtaposed with a light-hearted bongo backbeat.

Björn Yttling, the band's bassist and keyboardist, says via phone from an indie-rock festival in Gurten, Switzerland, that the lyrical dichotomy is no coincidence. "You don't want to go only dark or only happy," he says, his speaking voice featuring a slight accent that all but disappears when he sings. "If you have gloomy lyrics, you maybe want to have some happy-trappy music to pep it up a bit. I think that's in every song we do, we try to not only do just one thing."

Peter Bjorn and John: Whistlin', workin'.

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Now, PB&J isn't the first Swedish act to combine melancholic lyrics with catchy pop rhythms: The trio's preceded by Jens Lekman, and followed by Loney, dear in this regard. And while perhaps Sweden's best-known contemporary act, PB&J is hardly alone in its bubblegum-pop styling. The geographically confused I'm From Barcelona easily rivals PB&J on its own debut album, Let Me Introduce My Friends, at least in terms of carefree song craftsmanship.

But what separates the songs of Peter Björn and John from those of its peers is their depth; the men display a talent for writing lyrics that are simultaneously bleak and hopeful. "Objects of My Affection," for example, darkly broods, "Some days, I just lie around and hardly exist/And can't tell apart what I'm eating from my hand or my wrist," before concluding, "Was I more alive then than I am now?/I happily have to disagree/I laugh more often now, I cry more often now/I am more me," over a guitar, drum and bass crescendo that is equal parts Morrissey and Clap Your Hands Say Yeah.

To achieve this sound, Björn, who was also the producer for Writer's Block, describes a recording process as counterintuitive as the songs themselves. By combining individual sounds that Björn refers to as "dirty" or "bad," they produce songs that, when taken as a whole, sound spotless. "I want to include the rough parts, oddly, because it's very easy to record clean sounds nowadays," he says. "When I hear a song on the radio where they have just recorded like it should be, very clean, I just turn it off. On 'Young Folks' for example, almost everything is run through a string reverb."

The trio also decided to shun an instrument that traditionally anchors pop music. "We decided on this record we didn't want any tambourines," Björn says. "We were kind of fed up with tambourines. People always push the tambourine on the chorus of the song, they record with maybe no thought behind it. Maybe we ourselves did that before, so we were bored with the tambourine thing and wanted more maracas."

The seeds for PB&J's bittersweet pop aesthetic were sewn in the mid-'90s, when pop- and twee-leaning bands such as Roxette, Eggstone and the Cardigans emerged from a Swedish scene that was struggling to find its identity in the wake of an Ace of Base-driven dance-pop craze. In addition to opening the door to U.S. commercial success with its hit, "Lovefool," the Cardigans and its contemporaries inspired a new generation of pop acts, PB&J included.

"When we grew up, when we started our band, me and Peter, we listened to the Cardigans, like that first album [1994's Emmerdale]," Björn says. "We really like that stuff."

But the current lineup of Peter Björn and John didn't officially coalesce until the former two  who had been playing in various bands together for eight years  moved to Stockholm in 1999 and met drummer John Eriksson. After a self-titled release in 2002, the trio began garnering critical acclaim for its second album, 2005's Falling Out, which contained post-punk songs with the usual dark-sound-plus-dark-lyrics equation.

The success of 2006's Writer's Block coincided with the group's decision to share lead vocal duties among all three members and embark on extensive tours. The latter has helped the band earn a reputation for live performances that transcend its recorded material. Many of the songs are treated with new arrangements, such as Björn's signature number "Amsterdam," which is stripped down to a rumbling bass and snare drum, Peter's whistling, Björn's baritone  and yes, maracas. "Young Folks" yields an impressive display of musical dexterity from Peter, in which he simultaneously plays maracas, bounces around the stage and produces a perfectly pitched whistle.

"You don't want to just hear a copy of the album when you go to a live show," Björn says. "We try to use a bit more improvisation. We've played together for eight years, we know each other, so at the spur of moment we can come up with stuff."

He also explains how the band's shift to more accessible song structures on Writer's Block aided its rise in popularity. "We play in a more consequential way now," he says. "We don't fool around with the basic pattern or structure like we used to. This record we tried to do more like Devo, more of a pattern of a hip-hop dance-y feel to everything. We didn't want any surprises in the last part of a song. It makes the song stronger in a way, you get the overall feel [of the song] and you never lose that."

But while the production that creates the band's sparkly indie-pop sound is clearly self-conscious, the divergent lyrics that ultimately define Writer's Block are less deliberate. "We write about things that have happened in our lives," Björn says. "We didn't really have a plan with lyrics beforehand  but it seemed when you put it all together, it was kind of a cohesive thing. That's always something that happens after, even if you didn't plan it."